Peter t



(No Model.) P. T. COFFIEL-D.

TAP

No. 428,808. Patented May 27, 1890.

UNIT STATES PATENT OFFICE.

PETER T. COFFIELD, OF NEW OARLISLE, ASSIGNOR TO THE SUPERIOR MACHINECOMPANY, OF SPRINGFIELD, OHIO.

TAP.

SPECIFICATION forming part of Letters Patent No. 428,803, dated May 27,1890.

Application filed November 11, 1889. Serial No. 329,837. (No model.)

To alt whom it ntwy concern.-

Be 1t known that 1, PETER T. OOEFIELD, a

citizen of the United States, residing at New Oarlisle, in the county ofClark and State of Ohio, have invented certain new and usefulImprovements in Expansible and Collapsible Taps, of which the followingis a specifi cation, reference being had therein to the accompanyingdrawings.

This invention relates to certain new and useful improvements inexpansible and collapsible taps for cutting screw-threads, and speciallyinternal or female threads, the tool being adapted to be mounted in thespindle of a drill-press or lathe.

The object of the invention is to provide a simple and inexpensivedevice so organized that the taps may be readily adjusted in and outthrough the manipulation of a single central adj usting-bolt andintermediate devices, which, upon operating the bolt, permit a change ofthe position of the heels of the taps on tangential cam-surfaces,whereby the adj ustment of the taps is effected.

Another object of the invention is to adapt that part of the tool calledthe sleeve,which carries the taps, to be made of various externaldiameters, and carry different lengths of taps to constitute the variousstandard sizes, and to adapt the said different-sized sleeves to be usedupon the same arbor.

In the accompanying drawings, forming a part of this specification, andin which like letters indicate corresponding parts, Figure 1representsalongitudinal sectional view of my improved tool; Fig. 2, afront elevation thereof with a portion of the cap broken away to showthe arrangement of the parts; Fig. 3, a view looking down upon the tool,as seen in Fig. 1,with a portion of the sleeve broken away; Fig. 4, atransverse sectional view on the line X X of Fig. 1, looking in thedirection of the arrow; and Fig. 5, an end view of the cam.

The letter A designates the head of the tool, from one end of whichprojects a tapering mandrel 13, having its extreme end flattened at C,and adapted to be carried by the spindle of a drill-press or of a lathe,and having projecting from the other end a stout arbor E.

This arbor is centrally bored at F, the portion G of which isscrew-threaded to receive the adjusting-bolt H, whose outer end isadapted to receive a wrench and whose inner end is preferably somewhatpointed, as shown at 1, whereby it conveniently engages with a slidingdog J. The shank K of this dog is fitted to slide in the central bore ofthe arbor, and is normally projected toward the adjusting-screw by meansof a spring, preferably a spiral spring L, located in the bore behindthe shank, as seen in Fig. 1. The arbor is slotted at M, and the dog isprojected through this slot and somewhat beyond the arbor, and isbeveled on one side, as shown at O.

The letter Pdesignates astout sleeve,which is rotatably fitted upon thearbor E and is' ring V, whose ends meet but are not joined.

Each tap has a notclrWV, in which this ring is placed, and its tendencyis to draw the taps inward and toward the center.

I will now refer to the tangential cam-surfaces by which the taps areexpanded, the spring-ring V acting to collapse them, as just suggested.These cam-surfaces are formed on the periphery of the arbor E and nearits front end, as shown at Y. Each cam, of which there is one for eachtap, comprises a curved face a and a depression I), and terminates in ashoulder 0. Each tap has its inner face curved to form a cam-face (Z,which rides upon a cam Y The part of the cams which is in contact withthe taps, respectively, determines the diameter from one diametricaltapto the other. This position is determined by the adjustment of the dog Jin the slot M and with respect to the wall R of the slot Q. Thisadjustment is effected by means of the the drill-spindle.

spring L and the bolt II. It willbe observed that when the tool isoperated the arbor will rotate within the sleeve without moving thelatter until the dog J reaches the wall R,and this it will do sooner orlater, according to its position in the slot. \Vhen near the rear orupper end of the slot, (according to whether the tool is in ahorizontalor vertical position,) it will reach the wall after a veryshort move ment of the arbor, and therefore the cams will move but avery slightdistance and cause the taps to expand but slightly. Should,however, the dog be adjusted to the other extreme end of the slot, thecams will rotate a greater distance within the sleeve before the dogwill reach the wall It, and therefore the whole extreme diameter of thecams will pass into contact with the taps, and hence expand them to agreater degree.

It will also be understood that a reversed motion of thearbor will carrythe dog against the axial wall of the slot Q, and hence move thecontracted diameter of the cam into contact with the taps and finallybring the depressions I) opposite to the taps. During all this reversedmotion the contracting force of the spring-ring V has been collapsingthe taps, so that they are drawn into the depressions Z) and freed fromthe threads which they have cut in the article undergoing treatment. Theshoulders c by this time reach the taps and they and the sleeve arerotated in the reverse direction with the arbor as the latter is run ina longitudinal direction by backing If the tool is used in alathe-spindle, the reverse movementwould collapse the dies in the mannerjust described, when the tail-stock of the lathe or slide-rest,whichever might be carrying the article under treatment, would be backedaway from the tool. A jam-nut c is carried by the bolt II and serves thepurpose of locking the bolt, as also that of holding in place thecap-plate j", which is a metallic disk fitting against the end of thearbor and extending over the taps and covering the ring V. It keeps thetaps from dropping out of the slots S and prevents the ring from workingout of the notches ll in the taps. I also prefer to place a collar orband 9 over the sleeve, so as to cover the slots M and Q and inclose thedog and inner end of the bolt II.

It will be observed that a simple manipulation of the bolt ll, whoselocation makes it easy of access, is all that is needed to adjust thetaps outward, which makes the tool convenient and easily adjusted inpractical use.

It will be observed from the dotted lines shown at 7L in Fig. 1 that thediameter of the sleeve may be increased over that shown in full lines,for the purpose of supporting and properly holding longer taps, so as toincrease thediameter of the tool measured by diametrieal taps. It willalso be observed that the diameter of the sleeve may be decreased ascompared to that shown in full lines, so as to make a smaller tool. Itwill be understood in this connection that the same mandrel and arbormay be used with the various sizes of sleeves, so that while the toolwill be manufactured oi": the standard sizes as regards the sleeves andthe lengths of the taps the same head will answer for the various sizes.This has, among other advantages, that of economy in manufacture, whilecovering a wide range of sizes.

l ollowing the subject of adj usting the taps, it will be understoodthat the primary purpose of adjusting them outward is to compensate forthe reduction in the diameter occasioned by the wear of the taps and thesharpening of them from time to time. lly the manipulation of the boltll the dog J and its operation in connection with the oblique wall R, asalso by the operation of the cam Y, this adjustment of the taps isquickly and eiiectively made. Incidentally this adjustment of the tapswill suffice to compensate for different sizes; but the main object ofthe adjustment is to maintain the standard size or diameter from tap totap,notwithstanding the constant wear of the taps.

It will be noticed that the forward end wall of the slot Q stands withinthe length of the slot M, and thatthe length of the shank portion of thedog, measured from the extreme ends, is sufficient to prevent the shankproper of the dog from getting out of theborebefore the dog is opposedby said forward wall.

llaving thus fully described my invention, what I claim as new, anddesire to secure by Letters Patent, is

1. In an expansible and collapsible tap, the combination, with a headhaving an arbor, an adjusting screw, an adjustable dog, and cams carriedby the arbor, of a sleeve mounted upon the arbor and having an obliquewall with which the dog engages, taps carried by the sleeve, and meansto collapse the taps, the oblique wall admitting of differentparts ofthe cams being adjusted to the taps.

2. In an expansible and collapsible tap, the combination, with a head,its mandrel and its arbor, the latter having cam-surfaces, a centralbore and a radial slot, an adj listing-screw, a sliding dog,and anactuating-spring for the latter mounted in said bore, the dog projectingthrough said slot, of a sleeve mounted upon the arbor, having a slotwith an oblique wall adjacent to said dog and radial slots, taps mountedin said slots, and means to collapse them and maintain their contactwith the cam-surfaces.

In an expansible and collapsible tap, the combination, with a head, itsmandrel and its arbor centrally bored and radially slotted, and havingtangential cam surfaces with notches and shoulders, an adjusting-bolt, asliding dog, and its actuating-s1) ring mounted in said bore, the dogextending through said slot, of a sleeve rotatably mounted on the arbor,having a slot with an oblique wall and engaged by the dog, radial slots,taps mounted therein, a spring-ring to collapse the taps, a

covering-plate, and a jam-nut carried by the bolt.

4. In an expansible and collapsible tap, the combination, with a head,its mandrel and its arbor having a central bore and a radial slot, asleeve, and tap, of a dog slidingly mounted in the bore and extendingthrough the slot, a spring to actuate it, and an adjustable bolt mountedin the bore.

5. In an expansible and collapsible tap, a head, its mandrel and itsarbor, the latter having tangential cam surfaces, a central bore, and aradial slot, a sleeve, and tap.

6. I11 an expansible and collapsible tap, the combination, with an arborand a sleeve mounted thereon, an oblique Wall and alongitudinally-adjustable dog arranged so that the adjustment of the dogto a position along and against the wall will vary the position of thesleeve on the arbor in a radial direction, and means to adjust the saiddog.

'7. In an expansible and collapsible tap, a head, a sleeve provided witha radial slot, one wall of which is oblique, and with an encircling bandor collar applied to the exterior of the sleeve and adapted to inclosesaid slot, and taps carried by the sleeve.

8. In an expansible and collapsible tap, the combination, with an arborhaving a central bore and a radial slot, of a sleeve mounted upon saidarbor and having a radial slot, one end wall of which stands within thelength of the slot in the arbor, taps carried by the sleeve, and a dogslidingly mounted in the central bore and of greater length in the shankportion than the clearance of the slot in the sleeve.

9. In an expansible and collapsible tap, the combination, with an arborand a central bolt and a dog fitted to the arbor, of a sleeve mountedupon the arbor, the taps carried by the sleeve, a plate on the boltwhich holds the sleeve from slipping 01% the arbor, and a nut on thebolt which holds the plate.

In testimony whereof I aflix my signature in presence of two witnesses.

' PETER '1. COFFIELD.

Witnesses:

JOHN C. BASSETT, J12, WARREN HULL.

